Heat Transfer Technology Boosts HVAC Efficiency

Brazed plate heat exchangers are among the heat transfer technologies available for commercial buildings.

This week, a report titled, “Energy Recovery Ventilator Market by Technology Type (Plate Heat Exchanger, Heat Pipe Heat Exchanger, Rotary Heat Exchanger, Run-Around Coil), Application (Commercial, Residential), and Region (NA, EU, APAC, MEA, SA) – Global Forecast to 2022,” was published by MarketsandMarkets, a global research firm with U.S. operations based in Northbrook, IL. According to the report, this market is projected to grow from USD 1.97 Billion in 2017 to USD 3.37 Billion by 2022, at a CAGR of 11.4% from 2017 to 2022.

The report summary notes that among technology types, the plate heat exchanger segment is expected to lead the energy recovery ventilator market during the forecast period. The increasing demand for plate heat exchangers from the commercial and residential sectors to manage, control, and monitor energy consumption in buildings is expected to drive the growth of the plate heat exchanger technology type segment of the energy recovery ventilator market from 2017 to 2022.

With a focus on Brazed Plate Heat Exchanger technology, and the potential for commercial and institutional buildings, the below article is contributed by SWEP, a global supplier of brazed plate heat exchangers (BPHEs) for HVAC, district energy, and industrial applications. Founded in 1983 in Sweden and acquired by the Dover Corporation in 1994, SWEP’s North American sales network is headquartered in Duluth, GA, with the manufacturing center located in Tulsa, OK.

Brazed Plate Heat Exchangers, For Buildings, District Energy, And More

Brazed plate heat exchangers (BPHEs) provide efficient, stable, and reliable performance in a robust and easily handled unit for air conditioning, refrigeration, heating, industrial, and district heating and cooling applications. Customized to achieve the required characteristics of each specific application, they ensure the highest performance with the lowest life cycle costs. BPHEs have no gaskets to repair or replace, providing savings on maintenance and repairs compared with traditional gasket plate heat exchangers (PHEs).

The BPHE is, in principle, constructed as a package of corrugated channel plates between front and rear cover-plate packages. The cover-plate packages consist of sealing plates, blind rings, and cover plates. Connections are mounted on the cover plates and can be customized to meet specific market and application requirements. During the vacuum-brazing process, a brazed joint is formed at every contact point between the base and the filler material. Brazing the plates together rather than bolting them between gaskets is what makes BPHE technology so efficient and compact as 95% of the material of the brazed unit is used for heat transfer. The compactness of the BPHE also enables a modular design, just like modular chillers, improving redundancy and reducing fouling.

plate heat exchangerBPHE technology has come a long way, and can now provide solutions in areas where it might not have been able to in the past. One main area today where BPHEs can provide optimized solutions is the district energy market, because the BPHEs are now available in high capacities that can deliver several megawatts of heating or cooling while maintaining a small footprint. For the past two decades, BPHEs have been consistently and rapidly replacing traditional shell & tube and PHE technologies in this market. In fact, BPHEs are now the preferred and most common heat exchanger technology in Europe’s district energy networks. Experience of their successful results in district heating and cooling applications is now winning trust in North America too.

District Energy Benefits From BPHE

One area where the cost can be significant is in the actual construction of a District Energy heating or cooling system. Building a new District Energy system is a major infrastructure project that requires the connecting of multiple buildings through a network of underground pipes. As mentioned, most of the existing District Energy systems in the U.S. are steam-based and, as such, utilize shell-and-tube or gasket plate heat exchanger (GPHE) technologies to transfer the hot water to the building’s substation.

However, both shell-and-tube and GPHE technologies possess operational shortcomings that prevent the system from operating at its full cost-effectiveness and efficiency. Specifically, the design of shell-and-tube heat exchangers does not allow for the most efficient transfer of the heating or cooling energy when the system is hot water-based. They are also difficult to clean and maintain since the entire tube nest needs to be removed, which can be difficult to account for in tight installations.

The main drawbacks in using a GPHE are connected to the first letter of its name, the “G,” or gasket. Namely, the gaskets need to be changed, especially when the GPHE is used in a heating application. Several conditions will require the gasket to be changed, including when they are worn out, which can be caused by both heat and temperature fluctuations, or during the cleaning process. Also, when the gaskets age or fail, they will leak, which can lead to additional costs for maintenance, replacement and, in severe cases, cleanup.

plate heat exchangerOne common shortcoming for both shell-and-tube heat exchangers and GPHEs is that they are large pieces of equipment that require a large footprint for installation. This can be a drawback for installations where optimizing the available square footage is a primary concern.

While the current installed base of District Energy systems in the U.S. relies on shell-and-tube and GPHEs to complete its heat-transfer operations, there is an alternative technology that is gaining in prominence. The brazed plate heat exchanger (BPHE) has none of the operational red flags that shell-and-tube and GPHE models possess, and can easily replace either technology in a District Energy system that has been retrofitted to be powered by hot or chilled water, rather than the currently preferred steam.

plate heat exchanger

Brazed plate technology offers numerous benefits such as space savings, increased efficiency, lower life cycle costs, smaller carbon footprint, built-in redundancy with modular design, and lower fouling potential plus CIP. BPHEs are already the standard in Europe, and the rest of the world is catching up quickly. With all these advantages, BPHEs will continue to expand into all kinds of applications and increasingly be chosen over the use of older heat exchanger technologies.